.header-sentinel {
  height: 1px;
  width: 1px;
  position: absolute;
  top: 0;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--dur-base) var(--ease-out),
              background var(--dur-base) var(--ease-out);
}

body.admin-bar .site-header { top: 32px; }
@media (max-width: 782px) { body.admin-bar .site-header { top: 46px; } }

.site-header.is-stuck {
  box-shadow: var(--sh-sticky);
  background: color-mix(in srgb, var(--color-surface) 92%, transparent);
  backdrop-filter: saturate(180%) blur(8px);
  -webkit-backdrop-filter: saturate(180%) blur(8px);
}

.site-header__inner {
  display: flex;
  align-items: center;
  gap: var(--sp-4);
  padding-block: var(--sp-3);
  min-height: var(--header-h);
  transition: min-height var(--dur-base) var(--ease-out),
              padding var(--dur-base) var(--ease-out);
}

.site-header.is-stuck .site-header__inner {
  min-height: var(--header-h-stuck);
  padding-block: var(--sp-2);
}

.site-logo {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-24);
  color: var(--color-ink);
  letter-spacing: var(--tracking-tight);
  flex-shrink: 0;
}

.site-logo:hover { color: var(--color-ink); }

.site-logo svg {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

.primary-nav {
  display: none;
}

@media (min-width: 1024px) {
  .primary-nav {
    display: flex;
    align-items: center;
    margin-left: var(--sp-4);
  }

  .primary-nav ul {
    display: flex;
    align-items: center;
    gap: var(--sp-2);
  }

  .primary-nav a {
    display: inline-flex;
    align-items: center;
    gap: var(--sp-1);
    padding: var(--sp-2) var(--sp-3);
    color: var(--color-ink);
    font-weight: var(--fw-medium);
    border-radius: var(--r-sm);
    transition: background var(--dur-fast) var(--ease-out),
                color var(--dur-fast) var(--ease-out);
    position: relative;
  }

  .primary-nav a:hover,
  .primary-nav li.current-menu-item > a {
    color: var(--color-primary);
    background: var(--color-primary-50);
  }

  .primary-nav li.menu-item-has-children > a::after {
    content: "";
    width: 8px;
    height: 8px;
    border-right: 2px solid currentColor;
    border-bottom: 2px solid currentColor;
    transform: translateY(-2px) rotate(45deg);
    margin-left: var(--sp-1);
    transition: transform var(--dur-fast) var(--ease-out);
  }

  .primary-nav li.menu-item-has-children:hover > a::after {
    transform: translateY(0) rotate(225deg);
  }

  .primary-nav .sub-menu {
    position: absolute;
    top: calc(100% + var(--sp-2));
    left: 0;
    min-width: 240px;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--r-md);
    box-shadow: var(--sh-2);
    padding: var(--sp-2);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity var(--dur-fast) var(--ease-out),
                transform var(--dur-fast) var(--ease-out),
                visibility var(--dur-fast) var(--ease-out);
    flex-direction: column;
    gap: 0;
  }

  .primary-nav li:hover > .sub-menu,
  .primary-nav li:focus-within > .sub-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
}

.header-search {
  display: none;
}

@media (min-width: 1024px) {
  .header-search {
    display: flex;
    flex: 1 1 auto;
    max-width: 420px;
    margin-left: auto;
    position: relative;
  }

  .header-search .search-input {
    min-height: 44px;
    padding-block: var(--sp-2);
    border-radius: var(--r-pill);
    font-size: var(--fs-14);
    background: var(--color-canvas-2);
    border-color: transparent;
  }

  .header-search .search-input:focus {
    background: var(--color-surface);
    border-color: var(--color-primary);
  }

  .header-search .search-icon {
    left: var(--sp-4);
    width: 18px;
    height: 18px;
  }

  .header-search .search-submit { display: none; }
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  margin-left: auto;
}

@media (min-width: 1024px) {
  .header-actions { margin-left: var(--sp-2); }
}

.header-action-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--r-sm);
  color: var(--color-ink);
  background: transparent;
  transition: background var(--dur-fast) var(--ease-out),
              color var(--dur-fast) var(--ease-out);
}

.header-action-btn:hover {
  background: var(--color-canvas-2);
  color: var(--color-primary);
}

.header-action-btn .icon {
  width: 20px;
  height: 20px;
}

.theme-toggle .icon-sun { display: none; }
[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

.lang-switcher {
  position: relative;
}

.lang-switcher-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: var(--sp-2) var(--sp-3);
  border-radius: var(--r-sm);
  color: var(--color-ink);
  font-weight: var(--fw-medium);
  font-size: var(--fs-14);
  background: transparent;
  min-height: 44px;
  transition: background var(--dur-fast) var(--ease-out);
}

.lang-switcher-btn:hover { background: var(--color-canvas-2); }

.lang-flag {
  width: 20px;
  height: 14px;
  border-radius: 2px;
  overflow: hidden;
  display: inline-flex;
  flex-shrink: 0;
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  color: var(--color-ink);
  border-radius: var(--r-sm);
}

@media (min-width: 1024px) {
  .nav-toggle { display: none; }
}

.nav-toggle:hover {
  background: var(--color-canvas-2);
}

.nav-toggle .icon {
  width: 22px;
  height: 22px;
}

.header-search-toggle {
  display: inline-flex;
}

@media (min-width: 1024px) {
  .header-search-toggle { display: none; }
}

.category-strip {
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.category-strip::-webkit-scrollbar { display: none; }

.site-header.is-stuck .category-strip {
  max-height: 0;
  overflow: hidden;
  border-top-color: transparent;
  transition: max-height var(--dur-base) var(--ease-out);
}

.category-strip__inner {
  display: flex;
  gap: var(--sp-2);
  padding-block: var(--sp-3);
  min-height: var(--header-strip-h);
  scroll-snap-type: x mandatory;
}

.category-chip {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: var(--sp-2) var(--sp-4);
  font-size: var(--fs-14);
  font-weight: var(--fw-medium);
  color: var(--color-ink-muted);
  background: var(--color-canvas-2);
  border-radius: var(--r-pill);
  white-space: nowrap;
  scroll-snap-align: start;
  transition: background var(--dur-fast) var(--ease-out),
              color var(--dur-fast) var(--ease-out);
}

.category-chip:hover,
.category-chip.is-active {
  background: var(--color-primary);
  color: #fff;
}

.category-chip .icon {
  width: 16px;
  height: 16px;
}